Split Ferrite Shielding for Wireless Power Capacitor Heating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power transmitting and receiving devices face issues with capacitor elements experiencing high temperatures due to induced currents, which can be exacerbated by the design of ferrite members used in these devices.
Innovation Solution
The devices are designed with a ferrite member comprising mutually spaced, split pieces of ferrite, where the power receiving coil is positioned on the lower surface and the power receiving capacitor on the upper surface, and vice versa for the power transmitting device, to minimize magnetic flux and induced currents within the closed loop circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If capacitor elements are disposed on a substrate to reduce size and cost, then capacitor size and cost are reduced, but induced currents pass through the capacitor elements causing high temperature
Solution Approach 1:
The ferrite member is divided into multiple split pieces that are mutually spaced apart. This segmentation creates magnetic flux barriers that intercept and redirect magnetic flux lines, preventing them from forming closed loops through the capacitor elements. The split pieces are positioned to strategically block magnetic flux paths while maintaining the overall magnetic shielding function, thereby reducing induced currents in the capacitor elements without requiring a solid ferrite block.
Solution Approach 2:
The split ferrite pieces act as intermediary magnetic flux barriers between the power transmitting/receiving coils and the capacitor elements. These intermediaries intercept and redirect magnetic flux, preventing direct coupling between the coils and capacitors. The ferrite material's high permeability allows it to attract and redirect magnetic flux lines away from the capacitor elements, reducing the induced currents that cause heating.
2Object-affected harmful factors
If ferrite member is formed of plurality of split pieces, then magnetic flux entering capacitor is reduced, but device complexity increases
Solution Approach 1:
The ferrite member is divided into multiple split pieces that are mutually spaced apart. This segmentation creates magnetic flux barriers that intercept and redirect magnetic flux lines, preventing them from forming closed loops through the capacitor elements. The split pieces are positioned to strategically block magnetic flux paths while maintaining the overall magnetic shielding function, thereby reducing induced currents in the capacitor elements without requiring a solid ferrite block.
Solution Approach 2:
The split ferrite pieces serve multiple functions simultaneously: they provide magnetic flux shielding, act as structural support elements, and create electrical isolation between different regions of the magnetic circuit. The same segmented structure that reduces magnetic flux coupling also simplifies assembly and allows for modular replacement, thereby reducing overall device complexity despite the segmented design.
3Power
If power transmitting and receiving devices use conventional capacitor design, then power transfer is achieved, but capacitor elements experience excessive heating due to induced currents
Solution Approach 1:
The ferrite member is divided into multiple split pieces that are mutually spaced apart. This segmentation creates magnetic flux barriers that intercept and redirect magnetic flux lines, preventing them from forming closed loops through the capacitor elements. The split pieces are positioned to strategically block magnetic flux paths while maintaining the overall magnetic shielding function, thereby reducing induced currents in the capacitor elements without requiring a solid ferrite block.
Solution Approach 2:
The invention converts the potentially harmful induced currents into beneficial magnetic flux redirection. The split ferrite pieces are strategically positioned to intercept magnetic flux that would otherwise induce harmful currents in the capacitors. By carefully designing the spacing and positioning of the ferrite split pieces, the magnetic flux is redirected through paths that do not involve the capacitor elements, thereby converting what would be a harmful effect into a controlled magnetic circuit design feature.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the magnitude of induced currents through the capacitor elements, thereby preventing excessive heating and allowing for efficient power transfer while minimizing ferrite usage and cost.
Implementation Method 1
a ferrite member including a plurality of mutually spaced, split pieces of ferrite... When the power transmitting and receiving devices transfer electric power therebetween, a magnetic flux is generated. The magnetic flux enters the power transmitting capacitor and the power receiving capacitor.
Implementation Method 2
When the power transmitting device and the power receiving device transfer electric power therebetween, the power transmitting coil has a current passing therethrough. The power receiving coil receives electric power from the power transmitting coil and thus a current is passing through the power receiving coil.
Implementation Method 3
the power transmitting device includes a power transmitting coil and a power transmitting capacitor connected to the power transmitting coil... The power receiving coil receives electric power from the power transmitting coil
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A power receiving device (5) includes: a ferrite member (81) including a plurality of mutually spaced, split pieces of ferrite (91, 92A, 92B1, 92B2); a power receiving coil (8) disposed on the side of a lower surface of the ferrite member (81); and a power receiving capacitor (9) disposed on the side of an upper surface of the ferrite member (81). The power receiving capacitor (9) has a closed loop circuit (111) including first and second wiring connections (116 and 117) and a plurality of capacitor elements (118A, 118B) connected in parallel between the first wiring connection (116) and the second wiring connection (117). When the power receiving capacitor (9) and the ferrite member (81) are seen from therebelow, the closed loop circuit (111) is located within the split piece of ferrite. A power transmitting device (3) has a corresponding structure